PD-L1 expression by either neoplastic or intratumoral inflammatory cells is related to tumor aggressiveness and suggests that the response to treatments targeting the PD-L1/PD-1 immune checkpoint could be restricted to particular HCC variants; thus, enrichment of these tumor subtypes in future clinical trials should be considered. (Hepatology 2016;64:2038-2046).

Bioprinting has emerged as a novel technological approach with the potential to address unsolved questions in the field of tissue engineering. We have recently shown that Laser Assisted Bioprinting (LAB), due to its unprecedented cell printing resolution and precision, is an attractive tool for the in situ printing of a bone substitute. Here, we show that LAB can be used for the in situ printing of mesenchymal stromal cells, associated with collagen and nano-hydroxyapatite, in order to favor bone regeneration, in a calvaria defect model in mice. Also, by testing different cell printing geometries, we show that different cellular arrangements impact on bone tissue regeneration. This work opens new avenues on the development of novel strategies, using in situ bioprinting, for the building of tissues, from the ground up.